| 摘要 |
Tri-n-butyl silicone is prepared by reacting n-butyl chloride with silicon chloroform in ether in the presence of sodium. Sodium chloride is removed by filtration, ether is removed, and the residue distilled. Similarly by substituting isoamyl chloride for n-butyl chloride tri-isoamyl silicane is obtained.ALSO:Tri and tetra-alkyl silicanes wherein the alkyl groups contain at least 2 carbon atoms are mixed with a solvent or another substance capable of lessening foam formation and added to liquids to diminish foam formation therein. In general, 0.01 to 0.5 per cent of the silicane suffices but the composition of the mixture itself can vary considerably. Specified silicanes are: tri-ethyl-; tri-(n-propyl)-; tri-isopropyl-; tri-(n-butyl)-; tri-isobutyl-; tri-isoamyl-; tri-(n-hexyl)-; tri-(2-ethyl butyl-1)-; tri-(n-octyl)-; tri-(2-ethyl-hexyl-1)-; tri-dodecyl-; tetra-ethyl-; and the tetra-isopropyl-; n-butyl-; isoamyl- and those containing a larger number of carbon atoms. Solvents soluble in water specified are isopropyl alcohol and polyhydric alcohols or their ethers, e.g. ethylene glycol; glycerine, diethylene glycol, ethylene glycol monoether and thiodiglycol; also ketones, e.g. acetone, whilst solvents sparingly soluble in water are aliphatic alcohols containing at least 5 carbon atoms especially branched chain ones, e.g. 2-ethyl-butanal, 2-ethyl-hexanal and also higher molecular weight alcohols, e.g. oleyl alcohol. Also phenols, e.g amyl phenols. Such sparingly water soluble solvents aid in diminishing foam formation as also do phosphoric acid esters, e.g. tri-(n-butyl) or tri-isobutyl-phosphate. |
